diff --git a/src/common/internal/test_group.ts b/src/common/internal/test_group.ts
index e1d0cde12d5c..aaaec9fe3f3a 100644
--- a/src/common/internal/test_group.ts
+++ b/src/common/internal/test_group.ts
@@ -620,7 +620,7 @@ class RunCaseSpecific implements RunCase {
             const subcasePrefix = 'subcase: ' + stringifyPublicParams(subParams);
             const subRec = new Proxy(rec, {
               get: (target, k: keyof TestCaseRecorder) => {
-                const prop = TestCaseRecorder.prototype[k];
+                const prop = rec[k] ?? TestCaseRecorder.prototype[k];
                 if (typeof prop === 'function') {
                   testHeartbeatCallback();
                   return function (...args: Parameters<typeof prop>) {